That Ultrabook label on thin Windows laptops has no real meaning, so be careful when you buy a new laptop

For all the years the Apple MacBook Air has been on the market, some PC maker has tried to copy it. Dell's Adamo is the best known of these poor man's Airs, and it's a good example of how users can tell they're not the real thing. Now, Intel has come up with the Ultrabook label to help PC makers out when trying to clone the MacBook Air.

You'll see a bunch of these Ultrabooks advertised for the holidays, in sleek metallic finishes and angular chassis. You'll see additional takes next year when Intel's power-efficient Atoms come on the market. And you'll see even more after that when the next-generation, power-efficient Core processors -- the ones used in serious computers like, um, the MacBook Air -- become available in 2013.

But there's a real problem with the Ultrabook label: It means practically nothing. There is no set of criteria PC makers must meet to use the Ultrabook label -- so it guarantees nothing, as I learned on a recent visit to Intel.

I asked how the Ultrabook prototypes I saw at Intel weren't just MacBook Air clones running Windows. (Keep in mind that a MacBook Air can run Windows, so why not get the real thing instead of a wannabe Ultrabook?) I couldn't get a clear answer from Erik Reid, Intel's general manager for mobile client products -- that is, laptops and the forthcoming Windows 8-powered tablets. After I pressed the issue a little more, he said there was no formal definition, as the capabilities would change over time, but the principles Intel was encouraging were thin, light, pleasing chassis designs; low power consumption and, thus, long battery life; fast startup; and better security.

Reid also noted that some PC makers were using the Ultrabook label on PCs that will be out this fall because they had begun development before Intel coined the term in July. In other words, the first batch of Ultrabook models meant to tempt you for your Christmas holiday shopping likely won't meet even those basic goals. (At a PC conference later, Intel CEO Paul Otellini echoed this distinction between vendors' use of the Ultrabook label and Intel's aspiratinos for it. Otellini said he didn't expect "real" Ultrabooks until spring.)

Reid did say that one Intel innovation would be common to all Ultrabooks: the use of Intel's Identity Protection Technology (IPT), which was introduced in the second-generation Core i3, i5, and i7 chip sets in January 2011. Basically, IPT is a separate chip from the processor that generates a unique identifier that acts as a second-factor authentication for user passwords, much like the Trusted Platform Module (TPM) chips proposed a few years back. Intel keeps a list of PCs that have IPT -- remember, it's not built in to every second-generation Core-based PC because it requires additional chips from Intel than just the Core processor. Applications and websites have to be written to look for and validate that unique identifier.